According to this link, U+00AD is a default ignorable code point.
What exactly is the purpose of these default ignorable code points? What is the harm if I want to render U+00AD ?
The link provides some information, but I am not really clear.
"U+00AD SOFT HYPHEN has a null default appearance: the appearance of ther-apist is simply "therapist"; no visible glyph. In linebreak processing, it indicates a possible intra-word break. At any intra-word break that is used for a line break — whether resulting from this character or by automatic process — a hyphen glyph (perhaps with spelling changes) or some other indication can be shown, depending on language and context."
Please clarify.